In this report, we found that gastric cancer cell lines adapted to growth in the presence of 10 μmol/L CDDP (MKN45 (CDDP)) showed enhanced ABCB1 and CDKN2A expression as compared with their CDDP-sensitive parental cell lines (MKN45 (0)) (Table 1). This evidence concerns the gene CDKN2A and gastric cancer.